1. Field of the Invention
The invention relates to a childproof and tamper-proof closure for containers, especially for medicines and/or chemicals, with an inner cap, which can be fastened on the mouth of the container by turning and removed from the container by turning it in the opposite direction and on which an outer cap is disposed, which covers the inner cap, can be twisted relative to it and can be shifted axially to it at right angles to the direction of rotation by a given amount, coupling projections, which can brought into engagement with one another in complementary fashion by the axial displacement of the outer cap on the inner cap in the direction of the interior of the container and, by the opposite axial displacement, on the other hand, be brought out of engagement with one another, being disposed on the inner cap and the outer cap, and a guarantee region, which interacts with at least one stop element or shear-off element, which is provided at the inner cap or at the mouth of the container, in such a manner, that the guarantee region is severed from the cap, to which it is integrally molded, already when the container is opened for the first time, being integrally molded at one of the caps of the closure over one or more break-off region or regions.
2. Description of the Related Art
Such screw cap closures, which are childproof as well as tamper proof are known in different forms. The childproof closures generally are constructed that, for unscrewing the closure, the outer cap must be compressed in the axial direction against the force of a spring holding the end faces of the outer and inner caps at a distance from one another, in order to bring the coupling projections into engagement in this way, which transfer a rotary motion, exerted on the outer cap, onto the inner cap. Two different tamper-proof systems have become known. For the one system, a locking ring is integrally joined over break-off cross members or a peripherally extending break-off seam to the edge of the inner cap on the container side and, with an annular ring protruding inwards, that is, to the neck of the container, or individual, inwardly protruding projections distributed in the circumferential direction, grip below a ring projection at the neck of the container. When this closure is unscrewed with the outer cap compressed, the inner cap unscrews from the thread of the neck of the container. The annular ring or the projections at the locking ring do not permit an axial displacement over the ring projection provided at the neck of the container, so that, in the region of the break-off cross members or the break-off seam, the locking ring tears off from the inner cap (U.S. Pat. Nos. 4,570,809 and 4,474,301). The other known tamper-proof system is based on the fact that, by means of a peripheral seam of weakness or individual break-off cross members in the end wall of the outer cap, an end wall section is formed, which can be broken out and is confronted by a projection protruding from the outer side of the end wall of the inner cap. If, for the purpose of a coupling engagement with the inner cap, the outer cap is pressed down in the axial direction, the end wall section, which can be broken out, comes to lie against the projection, is broken out upon further pressure and falls off from the outer cap, so that an opening is formed in the end wall, which indicates that at least the attempt has been made to open the closure (U.S. Pat. Nos. 4,801,028 and 4,669,620). The two tamper-proof systems described above are based on the fact that, when the closure is opened, an originally integral part of the closure necessarily is torn off or sheared off. However, practical experience has shown that a tamper-proof system, which is based on a locking ring that can be torn off, is not manipulation-proof in all cases. Especially when the plastic material of the inner cap is sufficiently elastic, the closure can be levered without tearing off the locking ring with elastic expansion over the annular protrusion at the neck of the container, the locking ring not being torn off. It is conceivable that the contents of the container can be removed and be replaced with a different product of lower value. On the other hand, the system with the end wall section, which can be broken out, has the disadvantage that the end wall section is broken out unintentionally without actually opening the container. For example, when the container is taken hold of clumsily, pressure can be exerted on the end wall of the outer cap and force open the end wall section without there having been access to the contents of the container. Such a container is then no longer saleable or the contents, contained therein, cannot be used for safety reasons, although they are still the original contents.